1. Field of the Invention
The present disclosure relates generally to a robot cleaner system. More particularly, the present disclosure relates to a robot cleaner system in which a robot cleaner can clean a surface to be cleaned while traveling by itself, and a control method thereof.
2. Description of the Related Art
Generally, a robot cleaner takes in a foreign substance, such as dust, dirt, or the like, from a surface to be cleaned while traveling around by itself without a user's manipulation within a cleaning area, and thus automatically cleans the cleaning area.
Such a robot cleaner has a distance sensor or a photographing unit, so that it cleans the cleaning area while confirming whether there is an obstacle located in front thereof or confirming a distance therefrom to a device or a stationery, a wall and the like installed in the cleaning area and thus moving to avoid a collision or obstruction thereto.
The robot cleaner as described above is provided with a left driving wheel, a right driving wheel, and a driven wheel, which are installed on a bottom of a cleaner body. The wheels are connected to and driven by driving motors, respectively. The driving motors are driven under the control of a control unit, so that the cleaner body can change a traveling direction thereof.
In addition, in the bottom of the cleaner body is a suction port. The suction port takes in the foreign substance, such as the dust, the dirt, or the like, from the surface to be cleaned. A suction force, which is applied to the suction port, is provided by a suction motor installed in the cleaner body. The suction port is connected to a separate dust collecting chamber formed in the cleaner body. Accordingly, the foreign substance contained in taken-in air is collected into and then removed from the dust collecting chamber. The robot cleaner as described above either cleans the cleaning area while traveling along a working path programmed beforehand or senses a traveling pattern formed on the surface to be cleaned and travels along the sensed traveling pattern. When the robot cleaner carries out the cleaning operation while traveling around by itself as described above, a control unit checks an amount of electric charge remaining in a battery and confirms whether the checked amount of electric charge is sufficient. If it is decided that the battery should be charged, the robot cleaner communicates with a charging station located at a predetermined position to search the position of the charging station, and moves to the searched position. Namely, for example, the control unit searches the position of the charging station while transmitting and receiving signals to and from the charging station, and drives the driving motors to move the cleaner body toward the charging station. Connecting terminals formed on the robot cleaner are connected to charging terminals formed on the charging station. When the connecting terminals and the charging terminals are connected with each other as described above, the control unit carries out a charging mode until the battery is fully charged with electricity. At this time, the robot cleaner stands by while stopping other modes, such as a cleaning mode, a wheel driving mode and the like.
In addition, as disclosed in Korean Patent No. 635828, the robot cleaner has a function, which sets the cleaning area by ‘a portion area’ or ‘the entire house’ and then carries out the cleaning operation according to the set area. In this case, the robot cleaner detects a height of a threshold, which forms a border between rooms, so that it crosses over the threshold or moves forward without crossing over the threshold.
However, the robot cleaner is usually delivered from a warehouse after a value for the threshold height is set up as a standard height value (20 mm). Accordingly, if because of a user's house structure, a threshold height of user's house has a value (for example, 30 mm) different from the standard height value set up in the robot cleaner, when the robot cleaner encounters a threshold in a state where the cleaning area thereof is set up as ‘the entire house’, it does not decide the detected threshold as a threshold, but as a precipice or the like. As a result, a problem occurs, in that it does not cross over the threshold, thereby causing the cleaning operation not to smoothly carry out according to the set area.